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From: Heiner Kallweit <hkallweit1@gmail.com>
To: Jean Delvare <jdelvare@suse.com>
Cc: "linux-i2c@vger.kernel.org" <linux-i2c@vger.kernel.org>
Subject: [PATCH 3/4] i2c: i801: Improve i801_block_transaction_byte_by_byte
Date: Sat, 4 Mar 2023 22:36:34 +0100	[thread overview]
Message-ID: <6686b692-0caf-734e-18cd-7879810b29cd@gmail.com> (raw)
In-Reply-To: <c39c8371-5ab5-45f7-d3cf-39ea50de0afb@gmail.com>

Here we don't have to write SMBHSTCNT in each iteration of the loop.
Bit SMBHSTCNT_START is internally cleared immediately, therefore
we don't have to touch the value of SMBHSTCNT until the last byte.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
 drivers/i2c/busses/i2c-i801.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
index 7641bd0ac..e1350a8cc 100644
--- a/drivers/i2c/busses/i2c-i801.c
+++ b/drivers/i2c/busses/i2c-i801.c
@@ -677,11 +677,11 @@ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv,
 	for (i = 1; i <= len; i++) {
 		if (i == len && read_write == I2C_SMBUS_READ)
 			smbcmd |= SMBHSTCNT_LAST_BYTE;
-		outb_p(smbcmd, SMBHSTCNT(priv));
 
 		if (i == 1)
-			outb_p(inb(SMBHSTCNT(priv)) | SMBHSTCNT_START,
-			       SMBHSTCNT(priv));
+			outb_p(smbcmd | SMBHSTCNT_START, SMBHSTCNT(priv));
+		else if (smbcmd & SMBHSTCNT_LAST_BYTE)
+			outb_p(smbcmd, SMBHSTCNT(priv));
 
 		status = i801_wait_byte_done(priv);
 		if (status)
-- 
2.39.2



  parent reply	other threads:[~2023-03-04 21:38 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-04 21:30 [PATCH 0/4] i2c: i801: next set of improvements Heiner Kallweit
2023-03-04 21:31 ` [PATCH 1/4] i2c: i801: Use i2c_mark_adapter_suspended/resumed Heiner Kallweit
2023-06-14 22:24   ` Andi Shyti
2023-06-15 21:17     ` Heiner Kallweit
2023-06-15 21:45       ` Andi Shyti
2023-06-16  6:00         ` Heiner Kallweit
2023-06-26 17:20     ` Jean Delvare
2023-08-27 16:20       ` Heiner Kallweit
2023-03-04 21:33 ` [PATCH 2/4] i2c: i801: Replace acpi_lock with I2C bus lock Heiner Kallweit
2023-06-14 22:31   ` Andi Shyti
2023-06-15 21:22     ` Heiner Kallweit
2023-06-15 21:49   ` Andi Shyti
2023-06-26 17:59   ` Jean Delvare
2023-08-27 16:21     ` Heiner Kallweit
2023-08-28  7:01       ` Jean Delvare
2023-09-15 14:01         ` Heiner Kallweit
2023-03-04 21:36 ` Heiner Kallweit [this message]
2023-06-14 22:32   ` [PATCH 3/4] i2c: i801: Improve i801_block_transaction_byte_by_byte Andi Shyti
2023-06-15 21:48   ` Andi Shyti
2023-06-27 13:46   ` Jean Delvare
2023-08-27 17:14     ` Heiner Kallweit
2023-08-28 13:27       ` Jean Delvare
2023-08-28 15:10         ` Jean Delvare
2023-08-29  6:08           ` Heiner Kallweit
2023-08-29  6:29         ` Heiner Kallweit
2023-03-04 21:37 ` [PATCH 4/4] i2c: i801: Switch to new macro DEFINE_SIMPLE_DEV_PM_OPS Heiner Kallweit
2023-06-14 22:37   ` Andi Shyti
2023-06-28  7:15   ` Jean Delvare
2023-09-22  9:54   ` Wolfram Sang
2023-09-22 10:20     ` Heiner Kallweit
2023-05-16 20:29 ` [PATCH 0/4] i2c: i801: next set of improvements Heiner Kallweit

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